Building envelopes of certain commercial and mixed use residential buildings include a curtain wall. The curtain wall of a building defines the appearance of the building and, more importantly, separates the interior controlled or conditioned space from the outside environment. The curtain wall is usually formed from a plurality of curtain wall panels that typically contain glass, metal, and/or stone. The curtain wall panels are attached to the building's structural elements via anchors and curtain wall panel hanging brackets (sometimes referred to as curtain wall panel brackets or panel brackets). The anchors are located at discrete attachment points along the edges of the building's concrete floor slabs. The anchors typically include embedments (sometimes referred to as embeds) that are each cast into a concrete floor slab and that may be located on the top of the slab, on the face of the slab, or beneath the slab. A panel bracket is attached to each embedment, and a curtain wall panel is hung from each panel bracket.
For a given concrete floor slab, before the concrete that forms that concrete floor slab is poured into the concrete form, an array of rebar, metallic cables, and/or other material used to reinforce the concrete floor slab is installed within the concrete form. Embedments are then positioned along an edge of the concrete form by a one or more workers using a tape measure and control lines provided by the general contractor. That is, the worker typically uses the tape measure to hand measure where to position each embedment along the edge of the concrete form using the control lines for reference, though in certain instances the embedments are positioned along the edge of the concrete form with the aid of survey equipment.
This installation process requires another measurement by the worker to assure the embedment has the proper edge spacing from the concrete form (i.e., to ensure the embedment is located at the proper distance from the edge of the concrete form). More specifically, after determining the position along the edge of the concrete form at which to attach the embedment, the worker must then use the tape measure to hand measure the distance of the embedment from the edge of the concrete form. The worker then anchors the embedment into place by either nailing the embedment to the concrete form, wire tying the embedment to rebar, or wire tying the embedment to scraps of lumber and then nailing the lumber to the concrete form such that the anchored embedment has the proper edge spacing from, and is positioned at the desired position along the edge of, the concrete form.
Concrete is then poured into the concrete form, typically via a high pressure concrete pumping hose. Concrete pumping hoses are heavy and unwieldy, and typically require multiple workers to control and operate the concrete pumping hose while walking on and around the rebar, metallic cables, and/or other reinforcing materials within the concrete form. As and after the concrete is being poured (pumped) into the concrete form, several workers level the poured concrete, which again involves the workers walking on and around the rebar, metallic cables, and/or other reinforcing materials. This movement, shifting, and jostling of the rebar, metallic cables, and/or other reinforcing materials, along with the vibration of the concrete pumping hose and the movement of the poured concrete itself, is problematic because it may alter the position of one or more of the embedments or dislodge one or more of the embedments.
Sometime after the concrete has been poured, each embedment must be located and exposed, which sometimes requires workers to chip away any concrete that may be covering the embedment. After the embedments are located and exposed, a survey is conducted to determine whether any of the embedments are potentially problematic. More specifically, the survey is conducted to determine whether any embedments are missing, any embedments are buried too deep within the concrete floor slab, any embedments are improperly positioned or misaligned, and/or whether any embedments conflict with other features of the building, in which case a panel bracket may not be able to be safely or properly mounted to that embedment. After the survey is completed, any problematic embedments must be fixed before construction can continue.
After any problematic embedments are fixed, workers mount a separate, individual panel bracket to each embedment using fasteners. Certain curtain wall panels include attachment fixtures that “hang” onto the panel brackets such that the curtain wall panels hang off of the panel brackets. These attachment fixtures often include a mechanism that enables some level adjustment to aid in leveling the curtain wall panels. These leveling mechanisms are seldom used, however, because they increase the time it takes to the hang the curtain wall panels, thereby increasing installation costs due to labor and equipment (such as cranes). As a result, the panel brackets are usually leveled per floor prior to the installation of the curtain wall panels. More specifically, for each floor of the building, the panel brackets on that floor are leveled relative to one another such that they are all planar and at a same elevation to ensure that the installed curtain wall will be level after the curtain wall panels are craned into position.
After the individual panel brackets are leveled, workers hoist the individual curtain wall panels and hang them onto the panel brackets at their respective final positions. The workers use a tower crane, truck crane, or mini crane to hoist and maneuver the curtain wall panels. Thus, in typical curtain wall installations, one curtain wall panel at a time is hoisted into position and hung off of one or more panel brackets. This one-at-a-time method of installing the curtain wall panels is necessitated by the use of discrete anchoring locations for the embedments and separate, individual panel brackets mounted to each embedment.
This one-at-a-time method of installing the curtain wall panels is time-consuming and expensive. If a mini crane is used to hoist and install the curtain wall panels, following the installation of each curtain wall panel or every other curtain wall panel, workers must reposition the mini-crane such that it is positioned directly over the next curtain wall panel's installation location. This constant repositioning of the mini-crane during installation extends installation time, which increases crane rental costs and labor costs, and increases the difficulty of installation and the likelihood of operator error during installation. In instances in which a tower crane or a truck crane is used to hoist and install the curtain wall panels, certain parts of the crane must be maneuvered (such as by rotating and/or extending or retracting the jib) prior to the hoisting and installation of each curtain panel to enable that curtain watt panel to be installed at the desired location. This constant repositioning of the parts of the tower or truck crane during installation also extends installation time, which increases crane rental costs and labor costs, and increases the difficulty of installation and the likelihood of operator error during installation.
Accordingly, there is a need for new apparatuses and methods for expediting the installation of curtain wall panels that solve the above problems.